1. Field of the Invention
The present invention relates generally to automated equipment control using video and other positioning inputs, and in particular to visually, automatically guiding between crop rows and against furrow row edges in agricultural applications.
2. Description of the Related Art
GNSS technology advanced vehicle and machine guidance and control in various technical fields, including the field of agricultural guidance by enabling reliable, accurate systems, which are relatively easy to use. GNSS guidance systems are adapted for displaying directional guidance information to assist operators with manually steering the vehicles. For example, the OUTBACK S™ steering guidance system, which is available from Hemisphere GPS LLC of Scottsdale, Ariz. and Hiawatha, Kans. and is covered by U.S. Pat. No. 6,539,303 and No. 6,711,501, which are incorporated herein by reference, includes an on-board computer capable of storing various straight-line and curved (“contour”) patterns. An advantage of this system is its ability to retain field-specific cultivating, planting, spraying, fertilizing, harvesting and other patterns in memory. This feature enables operators to accurately retrace such patterns. Another advantage relates to the ability to interrupt operations for subsequent resumption by referring to system-generated logs of previously treated areas.
Another type of GNSS vehicle guidance equipment automatically steers the vehicle along all or part of its travel path and can also control an agricultural procedure or operation, such as spraying, planting, tilling, harvesting, etc. Examples of such equipment are shown in U.S. Pat. No. 7,142,956, which is incorporated herein by reference. U.S. Patent Application Publication No. 2004/0186644 shows satellite-based vehicle guidance control in straight and contour modes, and is also incorporated herein by reference. U.S. Pat. No. 7,162,348 is incorporated herein by reference and discloses an articulated equipment position control system and method whereby a working component, such as an implement, can be guided independently of a motive component, such as a tractor. The implement can optionally be equipped with its own GNSS antenna and/or receiver for interacting with a tractor-mounted GNSS system.
Ideally crops would be planted in perfectly straight, evenly-spaced rows. Guidance through such fields would consist of following relatively simple straight-line patterns. Such guidance modes are commonly referred to as straight line or “A-B” in reference to the equipment traveling in a straight line between point A and point B in a repeating pattern in order to cover an entire field, which is typically flat and rectangular and therefore efficiently divided into multiple, parallel swaths. However, field conditions in many areas are not suitable for A-B guidance. For example, hilly terrain sometimes requires the formation of constant-elevation terraces.
Guidance systems accommodate such irregular conditions by operating in “contour following” modes consisting of curvilinear tracks defined by multiple GNSS points along which the equipment is guided. Initial planting passes made with manual and visually-guided navigation, which may or may not be supplemented with GNSS navigational aids, can cause crop rows to deviate from straight lines. Accommodating such irregular crop rows in subsequent operations (e.g., spraying and harvesting) may require the equipment to deviate from straight-line passes.
“Tramline” (sometimes referred to as “match tracks”) is another operating mode available with some modern GNSS guidance systems. In tramline operating mode the existing crop rows are relatively well protected because the equipment follows or “matches” the previously-driven passes. The equipment wheels or tracks are thus confined between the crop rows. Machine damage from running over crops is thus avoided, or at least minimized.
Notwithstanding recent advances in GNSS-based guidance accuracy, the natural irregularities of row crop cultivation tend to compromise the effectiveness of navigation based solely on location-finding from satellite signals. Moreover, satellite signals are occasionally lost due to interference from atmospheric conditions, weather and electromagnetic fields (EMF). There are various levels of differential accuracy available for GNSS. The use of these can cause offsets and drifts, especially over the crop growth season from field preparation to harvesting. In order to compensate for such lapses in GNSS reception, inertial navigation systems (INS) with gyroscopes has been utilized for relatively short-term, supplemental guidance input. Many systems accommodate operators overriding the automated functions. For example, an operator may respond to observed, actual field conditions in order to maintain the equipment on course. A system integrating input signals from GNSS, inertial and visual guidance subsystems could optimize guidance solutions in various conditions. Moreover, visually guiding with cameras directed at the crop rows or the furrow row edges can provide relatively accurate positioning solutions, supplemented by GNSS and gyro inputs. The GNSS receivers and inertial devices (i.e. gyroscopes) can be less accurate, and hence less expensive, in such systems where the most precise positioning inputs are from visual references. Highly accurate (i.e. centimeter level) positioning with GNSS signals alone typically involves one or more relatively sophisticated and expensive receivers, and often involves subscription-based broadcast corrections or localized broadcasts from real-time kinematic (RTK) base station GNSS equipment. Custom applicators, who use their equipment on multiple farms, need guidance equipment capable of universal operation for optimizing their productivity while minimizing crop damage. Such equipment should be usable by operators with minimal training operating at optimal speeds and should have the capacity for storing and recalling field data for reuse, for example from season-to-season. Higher equipment speeds also tend to create autosteering discrepancies, which can lead to crop damage from equipment overruns. Hence, visual referencing can accommodate faster equipment even with relatively basic GNSS/INS guidance receivers and sensors. Fields are sometimes planted using a variety of guidance methods, and guidance equipment used in subsequent operations should be responsive to actual field conditions, such as crop locations, without undue reliance on previous equipment and data recorded thereby, which may or may not be sufficiently accurate for subsequent operations.
Heretofore there has not been available a GNSS, inertial and visual guidance and control system and method with the advantages and features of the present invention.